Aggr with set analysis in a line chart

[#1]

Hello everyone,

I'm new to qlikview and  I need your help.

What I have:

Status	checkpoint	date	nproblems
2	A	20-out	10
2	B	21-out	35
2	B	24-out	10
2	B	25-out	20
3	A	25-out	10
3	B	30-out	20

Line chart:

Dimension:

status

expression used:

sum(aggr(-(max({<checkpoint={'B'}>} date) - min({<checkpoint={'A'}>} date) > 3),Status, nproblems)) 

when i have the status filter selected it shows me the number of problems that i have to solve and that are exceeding the SLA(-(max({<checkpoint={'B'}>} date) - min({<checkpoint={'A'}>} date) > 3).

If I select status 2 it appears on the chart line the number 30. If I select status 3 it shows on the chart line the number 20.  Meaning that if i choose in my filters just one status it gives me the correct result for that status.

My problem: the filter status has to have always one value selected and my client wants to see in a line chart the evolution of the status selected regarding the last 3 status(1,2,3,4).

So, if i have the status 3 selected, it must appear in the line chart the information regarding the status 3 and 2 for the table that I indicated above.

I think that the main problem is regarding the date, because it is always different and unpredictable and its used in the expression.

Can you help me finding a solution for this?

Best regards,

Joana